旋翼/涵道风扇共轴式无人直升机操稳特性研究

考虑旋翼下洗气流影响及涵道环括作用,将Pitt/Peter动态入流模型推广到旋翼/涵道风扇升力系统建模中,结合风扇/涵道机身组合吹风试验数据,建立了实用的旋翼/涵道风扇共轴式无人直升机全量数学模型.以据非线性模型得到的小扰动模型为基础,深入研究了旋翼/涵道风扇共轴式无人直升机不同前飞速度下的飞行动力学特性,包括稳定特性、操纵响应特性及耦合特性,并与常规布局直升机进行了对比.分析结果表明,旋翼/涵道风扇共轴式在横航向运动模态的稳定特性及操纵响应的耦合特性上具有明显区别于常规布局直升机的飞行动力学特性.所得结论与该型直升机实际飞行特性一致.

Stability and Control Analysis of Rotor/Ducted-fan based Unmanned Helicopter

Taken into consideration of the effect of rotor downwash and shrouding duct,the Pitt-Peters’ first harmonic non-uniform dynamic inflow model is extended to modeling the rotor/ducted fan propellant system.Combined with the data of wind tunnel experiment of assembled fan and duct fuselage,a practical nonlinear mathematical model of a full-scale rotor/ducted-fan helicopter is derived.The derived nonlinear model is linearized and the analysis of flight dynamics of the rotor/ducted-fan helicopter is conducted.The analysis results are compared with the flight dynamics of a conventional helicopter.It is indicated that the distinguishing features of the rotor/ducted-fan helicopter from the conventional helicopter are predominantly in the stability of lateral-directional motion modes at different flight speeds and the coupling characteristics of response to control inputs.